1. Field of the Invention
The present invention relates to the design and manufacture of imaging systems. More specifically, the present invention relates to the design and manufacture of staring sensor systems.
2. Description of the Related Art
Numerous imaging sensing technologies are known in the art. Certain sensors are preferred for particular applications and requirements. For example, visible sensors are easy to view, however, infrared sensors are more useful for imaging in conditions of low light levels or where the image my be obscured by smoke or weather conditions.
Unfortuantely, some applications require both sensing capabilities. In military applications, for example, an understanding of the reflectance and emission signature of targets of interest over a wide range of wavelengths is important to furthering the effectiveness of electro-optical sensors. It is also necessary to understand how varying atmospheric conditions can attenuate/degrade these signatures as they propagate through the atmosphere over extended ranges. Comparing and/or combining the image signature data from more than one spectral sub-band can provide additional information which enhances the ability to detect and identify certain military targets.
However, inasmuch as conventional imaging systems are designed for a particular portion of the electromagnetic spectrum, applications requiring the imaging of the visible and infrared portions of the spectrum, for example, typically required two separate sensors and a separate electronic signal processing system for each sensor. This approach was dictated by the fact that 1) most detectors can only cover a portion of the entire desired spectral range and 2) it is virtually impossible to design refractive optics which can provide equally high imaging performance across such a wide spectral range.
In addition to the high cost, size and weight associated with a multiple sensor approach to multispectral applications, the use of multiple sensors may force the incorporation of other costly features into the design. For example, the use of two separate sensors for military applications may require the provision of two apertures in armored vehicles.
Also, if it is desired to combine or blend the imagery from different spectral bands, this "data fusion" must be accomplished via digital post-processing of the separate imaging channels using electronics which add further to the overall cost of the system.
Further, if quantitative scene measurements are desired, the use of different optics and detectors (often with different array formats and responses) introduces additional measurement complexities.
Hence, there is a need in the art for a multispectral imaging system.